EP2188405A1

EP2188405A1 - Method for producing a metal-oxide-coated workpiece surface with predeterminable hydrophobic behaviour

Info

Publication number: EP2188405A1
Application number: EP08748374A
Authority: EP
Inventors: Eva Maria Moser
Original assignee: incoat GmbH
Current assignee: incoat GmbH
Priority date: 2007-08-13
Filing date: 2008-05-30
Publication date: 2010-05-26
Anticipated expiration: 2028-05-30
Also published as: WO2009021340A1; US20110287227A1; EP2188405B1; CN101790596A; CN101790596B; WO2009021340A9

Abstract

It is proposed to produce a workpiece (10) with a metal-oxide-coated surface (9) with a selectable degree of hydrophobic behaviour, by the surface of a substrate material (1) being provided at least in partial regions with a microstructure (2, 3) by mechanical embossing and subsequently being coated. The microstructuring is followed by depositing a hydrocarbon- or silicon-dioxide-containing protective layer (6) and/or at least one top layer (7), on the surface (9) of which the desired hydrophobic properties occur. The sterilizing and catalytic effect of the metal-oxide-containing top layer (7) is enhanced or produced by incorporation of metal-containing nanoparticles.

Description

Process for producing a metal-oxide-coated workpiece surface with specifiable hydrophobic behavior

The invention relates to a method for producing a metal-oxide-coated workpiece surface, with predeterminable hydrophobic behavior with a water contact angle (WCA) of greater than 90 ° and germ-killing on germs such as bacteria, viruses, fungi and microbes workpiece surface, as well as on a workpiece according to the preambles of claims 22 and 23.

The production of ceramic thin films such as the metal oxides SiO _x , AIO _x , ZnO _x , ITO, TiO _x and their hydroxides containing compounds on various materials is industrially with various PVD (Physical Vapor Deposition), CVD (Chemical Vapor Deposition) and PE-CVD (Plasma Enhanced Chemical Vapor Deposition) method is realized and is described in numerous textbooks, as in "Traite des materiaux", 4. Analysis et technologie des surfaces; Hans Jorg Mathieu, Erich Bergmann, Rene Gras; 2003; ISBN 2-88074-454-7. Also known is the secondary formation of carbonates on the metal oxide surfaces due to reactions with the environment. The germicidal, detoxifying and self-cleaning effect of a photocatalytically active, hydrophilic titanium dioxide surface is described in numerous publications and is attributed to the redox reactions in the band gap of the semiconductor titanium dioxide, which are caused by light exposure. In review by O. Carp, CL Huisman, A. Reller, Prog. Solid State Chem. 2004, vol. 32, N ⁰ 1-2 pp. 3-177, the manufacturing methods and the three areas of application (generation of electricity in solar cells, production and destruction of specific substances due to chemical reactions and the photoinduced superhyphrophilia) are compiled. In the literature, only titanium dioxide surfaces with hydrophilic behavior have been described so far. Also known is the germicidal (disinfecting, anti-microbial, bactericidal, virucidal, fungicidal) effect of workpiece surfaces coated with silver or other metals. As state of the art for the silver coating textiles is referred to the article by HJ. Lee, SY Yeo and SH Jeong in Journal of Materials Science 2003 vol. 38, No 10, pp. 2199-2204, for the Colloidal Silver Coating of Titanium Dioxide Particles, to the article by J. Keleher, J. Bashant, N. Heldt, L. Johnson, Y. Li in World Journal of Microbiology and Biotechnology 2002, Vol , No 2, pp. 133-139 and for the photolytic silver coating of titanium dioxide refer to the article by Mitsuyoshi Machida, Keiichiro Norimoto, Tamon Kimura in Journal of the American Ceramic Society 2005, 88 (1), 95-100. The wetting behavior of liquids - especially of water - on material surfaces plays an important role in many applications. Wetting is understood to mean the degree of adhesive contact of liquids on surfaces, in particular on solids. It refers to the ability of liquids to spread on a surface. An important case here is the hydrophobic behavior of a surface, ie the water-repellent behavior, in which the water is repelled at the surface and thereby, for example, drops form. Surfaces are called non-wettable, ie hydrophobic if the contact angle is> 90 °. The opposite is the hydrophilic behavior, which makes water well accepted on the surface. This wetting behavior is measured and defined by the so-called water contact angle (WCA). The better the wettability, the smaller is the contact angle occurring during wetting and is <90 °. The definition comes from the review by Huan Liu, Jin Zhai and Lei Jiang, Soft Matter, 2006, 2, 811-821. Ceramic, metal oxide-containing surfaces are hydrophilic. One of the disadvantages of the hydrophilic surface is the dripping of liquids. The workpiece surface is therefore moist for a long time and does not dry off. This condensation behavior can also hinder the removal of liquids and impurities as well as the problem-free cleaning of the surface. As a result, liquids and contents can not be completely transferred, the growth of germs and the corrosion of metals are favored. It is an object of the present invention to eliminate the disadvantages of the prior art. In particular, it is an object of the present invention to realize a method which makes it possible to treat material surfaces consisting of plastics, natural materials and metals in such a way that a metal-oxide-containing coated workpiece surface with a desired degree of hydrophobic germicidal behavior arises. In addition, it is an object of the present invention to be able to use already known and proven basic processes, which enables an economic producibility of the products. The implantation of metal-containing nanoparticles on the surface of the metal oxide covering layer achieves a germicidal and optionally anti-static protective effect. The plasma method used according to the invention for the production of the nanoparticles enables a substantial immobilization of the nanoparticles and thus a control of the metering of the release of the metal ions and the minimization of the risk of mobile nanoparticles. Especially in the medical field, the germicidal effect of metal ions - which takes place without exposure to light - be of great importance.

In the special case of the ceramic thin-film titanium dioxide, especially in the presence of the anatase modification, the germicidal effect is due to the photocatalytic activity under the action of light even without releasing metal ions. The implantation of metal particles in catalytic thin-film systems on the one hand significantly increases the catalytic activity and electrical conductivity, on the other hand, the germicidal effect of the workpiece surface is independent of the light exposure. In all variants, the inherently hydrophilic metal oxide surface is imparted hydrophobic behavior by microstructuring the workpiece surface. The changed condensation behavior causes a better transfer of liquids and contents as well as a better cleaning and drying of the workpiece surface. In the second variant, the hydrophobic effect is somewhat attenuated by the presence of nanostructuring of the substrate surface, but on the other hand, the catalytic activity of the titanium dioxide or zinc oxide layer is enhanced, which is advantageous for certain applications. The result is in any case an actively germicidal, detoxifying and self-cleaning workpiece surface, which is particularly important in the medical and pharmaceutical sector. The combination of up to three synergistic modifications (microstructure, metal-containing nanoparticles, titanium dioxide) results in a sustainable, permanently active self-cleaning, germ-killing workpiece surface. The tuning of these combination elements is crucial for the respective application in order to obtain an optimal effect.

This object is achieved according to the invention by the features of claims 1, 2, 3, 22 and 23. Further advantageous embodiments include the dependent claims. According to the invention, a workpiece is to be coated with a metal oxide-containing thin layer which has a hydrophobic and germicidal behavior with a selectable degree. Therefore, the surface of a substrate material is provided with microstructure by mechanical embossing at least in some areas and subsequently coated. For the production of the microstructure, the workpiece should consist of embossable material, such as a polymer, preferably a thermoplastic such as polypropylene or a metal, preferably a ductile metal such as copper, aluminum, steel and their alloys. For a metal, other methods such as shot peening or electrocorrosion can be used.

The plasma treatment is preferably carried out in a closed system in which the introduced process gases are pumped out with a vacuum pump. The respective working pressure range is adjustable over a wide range and can reach atmospheric pressure. The different processes allow the targeted creation of surfaces with the desired degree of wettability.

To produce a workpiece surface with predeterminable hydrophobic behavior with a water contact angle (WCA) of greater than 90 °, the following method steps are carried out according to the invention in the first variant: A substrate is used in which, at least partially, a line-like or lattice-like microstructure with indentations or elevations is impressed, which is formed from a multiplicity of structural elements hanging one another, whose individual dimensions are in the range from 3 μm to 50 μm, and that between the adjacent structural elements grave-shaped depressions or elevations with a depth in the range of 1 .mu.m to 10 .mu.m - preferably 3 .mu.m to 7 .mu.m - are formed, which around the structural elements having a width in the range of 3 microns to 11 microns - preferably 5 microns to 7 microns - are arranged;

After the microstructuring at least one cover layer is deposited in a vacuum chamber from a plasma discharge at least in some areas on the substrate, the at least one metal-containing and an oxygen-containing gas and / or a metal oxide-containing compound has a layer thickness in the range of 5.0 to 500 nm - preferably 10 bis 300 nm -,

To produce a polymeric workpiece surface with predeterminable hydrophobic behavior with a water contact angle (WCA) of greater than 90 ° and a germ-killing workpiece surface, the following method steps are carried out according to the invention in the second variant:

A substrate is used which consists at least on the surface of plastic and in this plastic surface is mechanically impressed at least in partial areas a line-like or lattice-like microstructure with depressions or elevations, which is formed from a plurality of contiguous structural elements whose individual dimensions in the Range of 3 microns to 50 microns, and that are formed between the adjacent structural elements grave-shaped depressions or ridges with a depth in the range of 1 .mu.m to 10 .mu.m, preferably 3 .mu.m to 7 .mu.m, which around the structural elements with a Width in the range of 3 microns to 11 microns - preferably 5 microns to 7 microns - are arranged;

• after the mechanical structuring, the substrate is treated in a vacuum chamber in at least two steps with a plasma discharge at least in partial areas, wherein in a first step the

At least oxygen or hydrogen is supplied to the plasma for chemical etching of the substrate surface and in the subsequent second step the plasma is added to at least one noble gas for ion etching of the substrate surface; After the plasma treatment, a protective layer containing hydrocarbon or silicium oxide is deposited in a vacuum chamber from a plasma discharge on the substrate at least in subregions to which at least one hydrocarbon-containing or at least one silicon-containing and oxygen-containing gas is supplied, and a layer thickness is produced is in the range of 2.0 nm to 70 nm, preferably in the range of 5.0 nm to 30 nm;

In a further step, at least one cover layer is deposited in a vacuum chamber from a plasma discharge at least in partial regions on the substrate which contains at least one metal-containing and one oxygen-containing gas and / or one metal oxide-containing compound

Layer thickness in the range of 5.0 to 100 nm, - preferably 10 to 50 nm - has.

In order to produce a workpiece surface with predeterminable hydrophobic behavior with a water contact angle (WCA) of greater than 90 ° and a workpiece surface having a germicidal effect, the following method steps are carried out according to the invention in the third variant:

A substrate is used in which, at least partially, a line-like or lattice-like microstructure with indentations or elevations is impressed, which is formed from a multiplicity of structure elements hanging from one another, their individual expansions are in the range of 3 microns to 50 microns, and that between the adjacent structural elements grave-shaped depressions or elevations with a depth in the range of 1 .mu.m to 10 .mu.m - preferably 3 .mu.m to 7 .mu.m - are formed, which around the structural elements having a width in the Range of 3 microns to 11 microns - preferably 5 microns to 7 microns - are arranged;

After the plasma treatment, a protective layer containing hydrocarbons or silicon oxide is deposited in a vacuum chamber from a plasma discharge on the substrate at least in subregions to which at least one hydrocarbon-containing or at least one silicon- and oxide-containing gas is supplied, and a layer thickness is generated which is in the Range from 2.0 nm to 500 nm, preferably in the range of 5.0 nm to 100 nm;

In a further step, at least one cover layer is deposited in a vacuum chamber from a plasma discharge at least in some areas on the substrate, to which a metal-containing and oxygen-containing gas and / or a metal oxide-containing compound is supplied, and that a layer thickness is generated, which in the range from 5.0 nm to 500 nm - preferably in the range of 10 nm - 300 nm. • in a further step, at least one type of metal-containing

Nanoparticles deposited in a vacuum chamber from a plasma discharge at least in some areas on the substrate to which at least one metal-containing gas is supplied, and that they have a particle size of 1.0 to 70 nm diameter - preferably 3.0 to 20 nm - have.

The substrate may be organic nature (polymer or natural materials) or inorganic nature (metals, alloys, ceramics, glass, etc.), or combinations thereof. Thermoplastics are preferably used as polymers, in the case of natural materials objects of paper, corn starch, cotton or viscose are conceivable. In the case of inorganic materials, these are preferably metallic substrate surfaces. In front- adjustable are in particular easily deformable substrates, such as aluminum foils, metal coated workpieces, etc. The substrate may be two or three-dimensional objects, such as a film, a plate, fabric, membrane, textile, thread, roll, hose, housing , Bottle, container, etc. The microstructure is advantageously embossed mechanically into the substrate material at the surface. Etching methods, for example electrochemical, electrocorrosive or chemical are also possible, but sometimes less economical. The mechanical embossing can be done in a known manner, for example with stamp presses or rollers. Hot-stamping is suitable for plastic substrates. The structuring is advantageously carried out with identical structural elements that repeat periodically, is advantageously of line-like or lattice-like design, and should take place at least in some areas on a substrate surface. Particularly suitable as plastic are thermoplastics and preferably polypropylene.

The hydrocarbon-containing protective layer is used for adhesion promotion and / or as a diffusion barrier as well as for the incorporation of metal-containing nanoparticles for the corrosion protection of metallic surfaces. In general, the protective layer protects against environmental influences and allows a stable behavior of the surface, so that degradation by the catalytic effect of the cover layer or corrosion of the substrate over several months to years can be substantially avoided or at least kept extremely low. The layer thickness of the hydrocarbon-containing or silicon-oxide-containing protective layer is 2.0 nm to 200 nm, preferably 5.0 nm to 100 nm, and in the case of transparent, colorless coatings 5.0 nm to 50 nm. The corrosion of the metallic substrate surface is on the one hand by the diffusion barrier of the protective layer, on the other hand additionally prevents the implantation of at least one type of metal-containing nanoparticles from 5.0 at% to 50 at%, preferably from 5.0 at% to 20 at%, by modifying the electrochemical potential of the metallic substrate. This cathodic or anodic protection by metal-containing nanoparticles is described in European Patent EP 1 251 975 B1. Due to the combination with the hydrophobic behavior of the coated surface, the work piece surface dries surface faster. As a result, the corrosion protection is additionally increased. In addition, the metal oxide-containing cover layer can give the workpiece scratch protection.

The implantation of metal-containing nanoparticles can increase the electrical conductivity of the metal-oxide-coated surface, thus producing an anti-static effect on an insulating workpiece.

In the three inventive embodiments, it is possible to carry out further process steps or coatings both between the substrate surface, the protective layer and the cover layer, as long as the microstructure and optionally the nanostructure are effectively imaged on the workpiece surface. Of course, any methods can be used for these process steps. Optionally, the hydrophobic effect may be enhanced with a rough workpiece surface, as described in the article by S. Shibuichi et al., Journal of Colloid and Interface Science 208, 287-294 (1998).

In addition, all of the described treatments of the substrate (1) can take place over the whole area or only in areas of area.

The invention will be explained below by way of example with reference to schematic figures:

Fig. 1 is a schematic representation of a production device for producing a workpiece surface with hydrophobic behavior;

2 shows in cross-section a substrate with a microstructured surface for the embodiment according to the invention;

FIG. 3 shows in cross section the substrate according to FIG. 2 with superimposed nanostructured surface 4 shows in cross section the substrate according to FIG. 3 with a protective layer on the microstructured and nanostructured surface;

5 shows in cross section the substrate according to FIG. 4 with the covering layer deposited on the protective layer, the workpiece surface with hydrophobic behavior;

6 shows an example of a layer structure with nanostructuring on a plastic substrate surface;

7a shows in cross-section a substrate with a microstructured surface and with a hydrocarbon-containing protective layer deposited thereon, which contains metal-containing nanoparticles and a cover layer with embedded nanoparticles for the third version of an inventive design;

Fig. 7b is a detail of Fig. 7a, enlarged

8 is a plan view of a microstructured substrate surface with differently sized and differently shaped structural elements, which may represent depressions or elevations;

9 shows in plan view an example of a microstructured substrate surface with structurally equally large and staggered structural elements, which can represent depressions or elevations;

10 shows in plan view a further example of a microstructured substrate surface with pyramidal, equal sized, non-offset structural elements, which may represent depressions or elevations;

11 shows in plan view a further example of a microstructured substrate surface with polygonal structural elements, which can represent depressions or elevations; 12 shows in plan view an example of a nanostructured substrate surface.

To produce a workpiece 10 having the desired degree of hydrophobic behavior, the substrate 1 is first provided with a microstructure on its surface by preferably mechanical embossing and then plasma-treated and / or coated in a vacuum system 20, as shown schematically in FIG. The embossing is carried out by known methods by embossing or pressing into the substrate surface 4 of the substrate 1 lying on a substrate carrier 27 with an embossing tool 27, such as an embossing punch or an embossing roll.

Advantageously, belt-shaped substrates, for example metal foils, can also be processed in a continuous process. Thereafter, the further processing steps are carried out in a vacuum system 20. The substrate 1 is transported into the vacuum system 20 through a lock 23 and stored there on a carrier or directly on an electrode 22 '. The vacuum system is evacuated via a pumping system 24. The working gas and possibly a carrier gas, such as preferably inert gases, such as argon or helium, are introduced into the vacuum chamber via gas inlet systems 25, 26 with the desired gas flow and working pressure in the chamber. A second electrode 22 is disposed opposite the first electrode 22 'and both electrodes are connected to a power supply 21 for generating the plasma. The plasma discharge can be fed at individual process steps with a direct current (DC) - power supply 21, as long as materials are involved, which have at least a certain electrical conductivity. For less highly conductive materials or for dielectric materials such as plastics, DC pulsed supplies or AC (AC) feeds 21 are preferred. Depending on the thickness and conductivity of the materials involved in the process, the height of the DC pulse frequency or the AC frequency is selected. For DC pulses can with Advantage frequencies from 50 kHz to 500 kHz can be used, both with unipolar, as well as bipolar pulses. Bipolar pulses may be asymmetric with only a small negative or positive contribution, with the turn-on time greater than the turn-off time. For AC supply, center frequencies from 10 kHz to 1.0 MHz can be used. Frequently used frequencies for the AC supply are in the RF range, which includes a range from 1.0 MHz to about 1.0 GHz. In certain cases, the use of microwaves is possible, with frequencies above 1.0 GHz. It may be advantageous to use magnetic-field-assisted plasma reactors.

Further coating sources, such as sputtering sources, preferably magnetron sources, can be provided in order to be able to produce additional layers by other methods than with the abovementioned plasma deposition (PECVD). For metal oxide-containing layers, such as, for example, TiO _x , a reactive process is preferably used in which the material to be sputtered contains titanium and oxygen as working gas 26 and a carrier gas 25, for example argon, are introduced into the process chamber 20. Also, the sputtering sources are operated with DC or AC power supplies, according to the above-mentioned information. The individual steps of the vacuum processes can also be carried out in different systems, but they are advantageously all carried out in the same system or in multi-chamber systems, if different process conditions are necessary or even a full automation is provided.

The individual steps for producing a workpiece 10 for the first variant of the invention will now be described with reference to FIGS. 2 to 6. In the second variant, a nanostructure 5 is created directly from a plastic substrate surface and superimposed on a microstructure 2, 3 on the substrate surface 4. FIG. 2 shows diagrammatically and in cross-section and in FIG. 8, as in a first step (a), a microstructure in the surface of the substrate 1 is mechanically embossed in order to obtain a surface 4 which is microstructured at least in some areas , The substrate 1 can in this case consist of different materials. The substrate 1 contains, for example, a different material 1b in the lower region than the upper region 1a which adjoins the substrate surface. The upper part consists of a polymer or metal 1a, and is the part of material in which the microstructure 2, 3 is embossed. As plastics thermoplastics, in particular Polyolephine are suitable. The microstructure consists of a line-like or lattice-like structure with mechanically impressed recesses or elevations 2, which is formed from a multiplicity of structure elements 3 which are suspended from one another and whose individual dimensions I, I 'are in the range from 3 μm to 50 μm. Between the adjoining structural elements 3, the depressions or elevations 2 are trench-shaped. These depressions or elevations 2 can also have interruptions in the circumference. The lines also need not be straight, but may have a zigzag or curvy shape.

The depth t, the trench-shaped depressions or elevations 2 is in the range of 1 .mu.m to 10 .mu.m, preferably 3 .mu.m to 7 .mu.m. The recesses or elevations may be different in a workpiece. The cross-sectional shape of the depressions or elevations 2 is not particularly important and can be selected according to practical manufacturing aspects.

The width b of the trench-shaped depressions or elevations 2 on the substrate surface 4 is in the range of 3 μm to 11 μm, preferably 5 μm to 7 μm. The dimensions I, I 'of the structural elements 3, that is to say the longest extent I and the smallest extent I' of the surface of the structural element 3, lie within the range of 3 μm to 50 μm.

The structural elements may have different shapes and sizes, as shown in Figures 2 and 8. Periodically, repeating patterns are advantageous for the practical realization, as shown for example in the schematic figures 9 to 11 in the plan view. FIG. 9 shows a microstructure with periodically arranged rectangular or square structural elements 3 with an arrangement offset from one another in a line. In FIG. 10 shows an example with square structural elements 3 in a non-staggered arrangement, and FIG. 11 shows a microstructure with periodically arranged polygonal structural elements 3. The gap width is 3 to 7 μm, preferably around 5 μm. It can also be seen from the figures that the width b of the recesses or elevations 2 is always smaller than the extent l ₁ 1 'of the adjacent structural elements 3.

In the second variant, in a next, second step, the production of a nanostructure 5, which is superimposed directly on the microstructure at least in Teilbereich and from the surface 4 made of plastic, here from the substrate surface made of plastic, with an at least two-stage plasma treatment is generated, as shown in Figure 3 in cross section. FIG. 12 shows, by way of example, a nanostructured surface 5, 5 'with randomly distributed worm-like structures as resulting from this method. The nanostructure 5 is formed in such a way that the height h of its elevations is set in the range from 20 nm to 120 nm and the distances or the extent w of the elevations lie in the range from 40 nm to 200 nm. After the mechanical structuring, the substrate 1 is treated in a vacuum chamber 20 in two steps with a plasma discharge, wherein in a first step the plasma at least oxygen or hydrogen is supplied to the chemical etching of the substrate surface 4 and at the subsequent second step the plasma at least one Noble gas, preferably argon, is added to the ion etching of the substrate surface 4. The length of the process control and adjustment of the process parameters, the above-mentioned achievable values can be selected. Further process steps can be carried out before the first step, or between the two steps, or after that, if necessary, for example, for cleaning the surfaces, such as the substrate. For the substrate cleaning, a plasma process for the ultrafine cleaning is preferably used after the coarse cleaning and fine cleaning, in which an inert gas such as argon or a corrosive working gas such as oxygen or hydrogen is supplied. Other methods of cleaning, such as ion etching are also possible.

In a metal substrate, the nanostructure may also be by a suitable plasma process or by anodic oxidation of metal-containing surfaces as described in S. Shibuichi, T. Yamamoto, T. Onda and K. Tsujii, Journal of Colloid and Interface Science 208, 287-294 (1998).

In variants two and three, in a next step, at least in partial regions, a protective layer 6 containing hydrocarbons and / or silicon oxide is deposited in a vacuum chamber 20 from a plasma discharge onto the substrate 1, as shown in FIG. For this purpose, a hydrocarbon-containing and / or silicon-containing and oxygen-containing gas is supplied to the plasma, a layer thickness 6 being produced which is in the range from 2.0 to 500 nm, preferably in the range from 5.0 to 100 nm. For transparent, colorless coatings, the layer thickness is 5.0 to 50 nm. With this protective layer 6, the workpiece 10 is protected against undesired changes due to harmful environmental influences. Such a protective layer 6 is advantageously designed as a dense, three-dimensionally highly crosslinked, plasma-polymerized scaffold which is flexible and soft or as hard and against mechanical damage (scratch protection, etc.).

The protective layer 6 should advantageously lower the permeability of oxygen by at least a factor of 10 compared with the uncoated, gas-permeable substrate 1. This can be measured, for example, by the plasma coating of a 12 μm thick polyethylene terephthalate film, which should have an oxygen permeability of less than 25 ml / m ² xTagxbar. The plasma-polymerized hydrocarbon-containing protective layer 6 doped with metal-containing nanoparticles and deposited on a metal surface has a corrosion-inhibiting effect which is expressed as follows: if the same protective layer is doped with metal-containing particles 11 in order to shift the electrochemical potential of the metal-containing substrate, the anti-corrosive effect is achieved also coated, non-microstructured substrate at least doubled.

In Figures 6, 7a and / b is enlarged and in cross-section a finished treated and coated workpiece 10 shown with a microstructured substrate surface 2, 3 with overlying protective layer 6 and a final cover layer 7 with the workpiece surface 9. Diese Combination now allows the production of workpiece surfaces 9, which have desired adjustable hydrophobic behavior, with a WCA greater than 90 °. For most applications, a WCA is advantageously set which is in the range of 90 ° to 160 °, preferably in the range of 110 ° to 160 °.

In Figures 7a and 7b is enlarged and shown in cross section the finished treated and coated workpiece 10. The substrate 1 with the microstructured substrate surface 2, 3 with overlying protective layer 6 with incorporated metal-containing nanoparticles 11 and overlying cover layer 7 with incorporated metal-containing nanoparticles 8.

According to variant 1, the workpiece 10 is equipped with a ceramic metal oxide-containing thin film having a thickness of 5.0 nm to 500 nm. Depending on the choice of ceramic cover layer (TiO ₂ , TiO _x (OH) _y , ZnO, AIO _x , SiO _x , ITO ((In) SnO ₂ ) and their hydroxides, etc.) by the metal-containing nanoparticles 8, the catalytic effect and / or the electrical conductivity (including anti-static effect) increases. Metal-containing nanoparticles 8 (Au, Ag, Pt, Pd, Rh, Cu, Fe, Ti, Zn, etc., or combinations thereof) are added at the grain boundaries at 5 at% to 50 at%, preferably 5 at% to 20 at% the metal oxide-containing surface in the outer surface, in particular in the uppermost atomic layers of the cover layer is incorporated. In the case of using, for example, gold- or silver-containing nanoparticles which have an inherent bactericidal action, the germs are killed by the released metal ions. According to variant 2, a workpiece 10 which is polymeric at least on the surface is provided with a nanostructure in order to increase the catalytic effect of the covering layer (TiO ₂ , ZnO, etc.) which, for example, enables detoxification on the workpiece surface. The germs are killed and then degraded by the photocatalytic redox reactions, ideally in the end products carbon dioxide and water.

If necessary, 2 metal-containing nanoparticles can also be embedded on the titanium dioxide surface in this variant. This is useful for many applications in the pharmaceutical and medical sector to achieve a germicidal effect even without exposure to light or an anti-static effect can.

According to variant 3, the workpiece 10 is coated with a catalytically active metal oxide (TiO ₂ , ZnO, etc.) and provided on the surface with metal-containing nanoparticles 8.

In all three variants, a titanium oxide-containing covering layer 7 having a thickness in the range from 5.0 nm to 500 nm can be deposited. Preferably, a photocatalytically active titanium dioxide layer is deposited, which has a self-cleaning, detoxifying surface and is additionally biocompatible. If it is an organic substrate (polymer, paper), the protective layer 6 is necessary before deposition of the titanium oxide-containing cover layer 7 in order to prevent possible degradation of the substrate. In the case of a metallic substrate, the titanium oxide-containing layer can be deposited as a protective layer 6 directly onto the substrate. The titanium oxide-containing layer is the topmost layer for this self-cleaning function in every application. The photocatalytic properties of this titanium oxide-containing cover layer 7 are increased by the surface enlargement of the substrate (microstructure and / or nanostructuring). In the presence of the "forced" hydrophobic surface property according to the invention, an organic contaminant is not only destroyed by photocatalytic methods, but also slightly wiped off. For all coatings, it is important, for example by choosing the layer thickness, to ensure that the microstructure 2, 3 and in particular also the nanostructure 5 on the workpiece surface 9 is at least still imaged in order to be able to fulfill the function.

The application of workpieces 10 with germicidal surfaces 9 is extremely far. The equipment of air conditioners, humidifiers, sanitary facilities, swimming pools, textiles and utensils in hospitals, pharmaceutical packaging, home and household items, etc. is imaginable. The combination with the hydrophobic behavior (anti-adhesion effect and possibly also anti-static effect) is important for ensuring the preservation of the surface properties of materials such as protection against contamination (residual contamination), economic and hygienic aspects (emptying of packaging, durability of pharmaceutical packaging such as tubes) and oxide formation of metals (corrosion).

The condensation behavior of the water, i. The dripping of the water is tailored to the use of the product by adjusting the hydrophobic performance characteristics. For an aluminum-containing surface in a heat exchanger or humidifier, cleaning maintenance can be massively reduced by the use of contaminant repellant and / or corrosion protected surfaces.

In the processing of materials such as metals and their alloys, the anti-adhesion effect reduces the costly removal of adhering dirt particles and protects the substrate from corrosion, especially when nanoparticles 11 move the electrochemical potential of the substrate at the interphase of the protective layer 6, a cathodic or to achieve anodic active protection.

In this context, the combination of the hydrophobic surface with the diffusion protection before the transfer of gases such as oxygen, nitrogen and carbon dioxide as well as a migration protection against undesired additives from the packaging in the contacting environment is important. Another advantage of the inventive development of plastic surfaces - in particular especially polypropylene - is the preservation of the sealability of the workpiece. If necessary, the preservation of the sealing properties can be increased by omitting treatment steps in these subregions.

The invention will now be explained with reference to further examples.

Description of the procedure for the treatment of a polypropylene film, which is for example 75 microns thick. The individual steps are listed in Table 1.

• 1st step: The microstructure is embossed into the polypropylene film with a heatable embossing roller and a rubber roller (hot stamping).

• Step 2: A vacuum chamber is evacuated to achieve a base pressure of lower than about 10 ^-2 mbar than the following working pressure. Subsequently, the working gases are introduced via mass flow controller in the vacuum chamber, the working pressure is controlled by a pressure gauge. In the second variant, a nanostructure of the microstructure is superimposed onto the microstructured substrate at least in some areas using a plasma method at room temperature.

1st process stage: RF plasma, room temperature, grounded substrate

Power range: 200 to 700 watts, typically at 400 watts working pressure: approx. 1.0 x 10 ^"2 mbar

Working gas: 10 to 60 sccm oxygen process time: 10 to 60 sec.

2nd process stage: RF plasma, room temperature, grounded substrate

Power range: 100 to 600 watts, typically at 300 watts working pressure: about 5 x 10 ^'4 mbar

Working gas: 10 to 50 sccm argon Process time: 10 to 60 sec. Process time: 10 to 60 sec.

• Step 3: The workpiece surface, which has been enlarged by the structuring, is provided with a three-dimensionally highly cross-linked, plasma polymerized hydrocarbon layer or DLC or a silicon oxide-containing layer. The structures are thereby fixed and protected from direct contact with the environment.

Example of process conditions: RF plasma, room temperature, substrate grounded, with or without bias voltage

Power range: 50 to 400 watts, typically at 100 watts Working pressure: 3 x 10 ^"2 mbar Gas mixture: 30 sccm C ₂ H ₂ , 15 sccm He

• 4th step: deposition of a photocatalytically active, titania-containing cover layer (containing anatase) at a substrate temperature of <8O ⁰ C.

Example of process conditions: Pulsed, reactive DC magnetron sputtering process with grounded substrate and variable magnetic field strength: Power: 2000 watts

Working pressure range: 1 x 10 ^"2 mbar to a few mbar, typically 5 x ^{10 -2} mbar gas mixture: 35 sccm of argon and 13 sccm of oxygen

• 5th step: deposition of metal-containing silver nanoparticles with a diameter of 3 to 20 nm on the photocatalytically active titanium oxide-containing top layer 7 at a substrate temperature of <5O ⁰ C.

Example for process conditions with a non-moving substrate and without a shutter: pulsed DC magnetron sputtering process with variable magnet gnetfeldstärke of a silver target and a substrate which is grounded or provided with a pulsed RF reference voltage (0 to -200 V).

Power: 10 to 50 watts, with rising and falling ramp each

0.5 sec and a plateau of 0.1 sec. Process time: 3 times 1.1 sec.

Working pressure range: 3 x 10 ³ to 3 x 10 ^"2 mbar, typically 9 x ^{10 -3} mbar gas mixture: 5 to 15 sccm of argon and 10 to 50 sccm Helium

Is preferred for all plasma processes, a working pressure ranging from 5 x 10 ^"4 mbar up to a few mbar, optionally, the working pressure can reach one atmosphere. The plasma processes are preferably carried out at room temperature (substrate may be thermostated, chilled or slightly heated), the workpiece is grounded or The layer thickness is varied in each case over the treatment time or speed of the sample transfer.

Table 1: Areas for measured water contact angles of titanium dioxide-containing or DLC-coated workpiece consisting of polypropylene with different microstructural elements. In the titanium dioxide-containing coated, microstructured substrates, the values are given with and without nanostructuring. For the coated, smooth or non-microstructured workpiece surface, the water contact angle and the surface energy are listed.

Explanation of the table: The water contact angles (WCA) were determined with a contact angle meter using the test liquid distilled water, according to the standards ASTM D5725-95 and ASTM D724 at 23 ° C and at 50% relative humidity.

A microstructured, with a DLC - or aC: H, or silane-containing a-Si / C: H - plasma-coated workpiece surface allows a stable, hydrophobic behavior with a WCA> 90 °. This workpiece surface is characterized by a surface energy of <37 mN / m - measured on the smooth workpiece surface - which is stable over a longer period of time. Without microstructuring, the surface has a water contact angle which, depending on the cover layer, can be set in a wide range and is within a range of 45 ° (TiO ₂ , SiO ₂ , etc.) according to the table, the surface energy being in the region of 49 mN / m (TiO ₂ , SiO ₂ , etc.) is moved.

If a workpiece surface is provided with the microstructure only in partial areas, the following situation can arise through the combination with the TiO ₂ cover layer (7):

- smooth part: hydrophilic behavior with WCA <90 ° - microstructured part: hydrophobic behavior with WCA> 90 °

The contact angle is significantly reduced by the combination with the nanostructure, but especially on the smooth, non-structured workpiece surface. Another concrete application of the hydrophobic surface is to prevent the ingress of water onto the material surface, which can have several adverse effects. Corrosion-causing particles (electrolytes, salts, etc.) can be transported to the surface or interface of the base material and react there. For corrosion protection, a fast-drying, hydrophobic surface is an advantage. The surface is therefore also contamination-repellent. The implantation of metal-containing nanoparticles in the protective layer 6 additionally protects the metallic substrate from corrosion if the electrochemical potential of the substrate is modified accordingly. Another advantage is that permeable gases and compounds can react with these metal-containing nanoparticles and thereby selectively influence the diffusion properties in a barrier layer. The protective effect is also adapted in this case by the combination of the at least four possible effects of the respective application: diffusion barrier, electrochemical effect, hydrophobic surface and an optionally germicidal surface.

In the processing of materials, the workpieces are often contaminated and must be subsequently cleaned. This residual contamination is particularly disadvantageous if the dirt particles adhere well to the workpiece surface. Here, the adjustment of the contact angle of the workpiece against the contaminating medium is particularly important and is in metals in a range of> 120 °.

The rapid and complete removal of deposits on the material surfaces is therefore optimized by tailor-made behavior (hydrophobic or hydrophilic). Applications in the pharmaceutical sector, such as the cleaning or impurity rejection from the outside of the packaging as well as the emptying of the contents of the packaging are of particular interest.

Claims

claims

1. A method for producing a workpiece surface (9) with predeterminable hydrophobic behavior with a water contact angle (WCA) of greater than 90 °, comprising the following steps:

a) it is a substrate (1) is used, in which at least in partial areas mechanically a line-like or lattice-like microstructure (2, 3) with depressions or elevations (2) is impressed, which is formed from a plurality of contiguous structural elements (3) whose individual dimensions (I, I ') are in the range of 3 μm to 50 μm, and in that trench-shaped depressions or elevations (2) having a depth in the range from 1 μm to 10 μm are formed between the adjoining structural elements (3) which are arranged around the Strukturele- elements (3) with a width in the range of 3 microns to 11 microns;

b) in a further step, at least one cover layer (7) is deposited in a vacuum chamber (20) from a plasma discharge at least in Teilbe- areas on the substrate (1) containing at least one metal-containing and an oxygen-containing gas and / or a metal oxide-containing compound and has a layer thickness in the range of 5.0 to 500 nm.

2. A method for producing a polymeric workpiece surface (9) with predeterminable hydrophobic behavior with a water contact angle (WCA) of greater than 90 ° and a germicidal workpiece surface comprising the following steps:

a) a substrate (1) is used, which consists of plastic (1a) at least on the surface (4) and in this plastic surface (4) a line-like or lattice-like microstructure (2, 3) with indentations or elevations (2) is impressed mechanically, at least in partial regions, which is formed from a multiplicity of structural elements (3) hanging from one another, whose individual extensions (I, I ') are in the range of 3 microns to 50 microns, and that between the adjacent

Structural elements (3) trench-shaped depressions or elevations (2) are formed with a depth in the range of 1 micron to 10 microns, which are arranged around the structural elements (3) having a width in the range of 3 microns to 11 microns;

b) after the mechanical structuring, the substrate (1) is treated in a vacuum chamber (20) in at least two steps with a plasma discharge at least in partial areas, wherein in a first step the plasma at least oxygen or hydrogen is supplied to the chemical etching of the substrate surface (4) and in the subsequent second step, the plasma is at least one noble gas is added to the ion etching of the substrate surface (4);

c) after the plasma treatment, a hydrocarbon-containing protective layer (6) is deposited in a vacuum chamber (20) from a plasma discharge onto the substrate (1) at least in subregions to which at least one hydrocarbon-containing gas is supplied and a layer thickness is generated is in the range of 2.0 nm to 70 nm;

d) in a further step, at least one cover layer (7) is deposited in a vacuum chamber (20) from a plasma discharge at least in partial areas on the substrate (1) containing at least one metal-containing and an oxygen-containing gas and / or a metal oxide-containing compound and a Layer thickness in the range of 5.0 to 100 nm.

3. A method for producing a workpiece surface (9) with predeterminable hydrophobic behavior with a water contact angle (WCA) of greater than 90 ° and a germicidal workpiece surface comprising the following steps:

b) after the plasma treatment, a hydrocarbon-containing protective layer (6) is deposited in a vacuum chamber (20) from a plasma discharge on the substrate (1) at least in partial areas, to which at least one hydrocarbon-containing gas is supplied, and that a layer thickness is generated, which is in the range from 2.0 nm to 500 nm;

c) in a further step, at least one cover layer (7) in a

Vacuum chamber (20) from a plasma discharge at least in some areas on the substrate (1) deposited, which is supplied to a metal-containing and oxygen-containing gas and / or a metal oxide-containing compound, and that a layer thickness is generated, which in the range of 5.0 nm to 500 nm is located. d) in a further step, at least one type of metal-containing nanoparticles (8) are deposited in a vacuum chamber (20) from a plasma discharge at least in some areas on the substrate (1), which at least one metal-containing gas is supplied, and that this particle size of 1.0 to 70 nm in diameter.

4. The method according to claim 1 or 2, characterized in that the outer surface (9) - in particular the uppermost atomic layers of the cover layer (7) - with at least one type of metal-containing nanoparticles (8) according to plasma treatment (3d) of the substrate ( 1), and that they have a particle size of 1.0 to 70 nm in diameter.

5. The method according to claim 1 to 4, characterized in that the cover layer (7) consists of a catalytically active metal oxide from the series of TiO ₂ and ZnO.

6. The method according to claim 1 to 5, characterized in that the outer surface (9) of the cover layer (7) with at least one type of metal-containing nanoparticles (8) according to plasma treatment (3d) of the substrate (1) from the A series of Ag, Au, Pt, Pd, Rh, Cu, Fe, Zn, Ti is incorporated.

7. The method according to claim 1 to 6, characterized in that the outer surface (9) - in particular the uppermost atomic layers of the cover layer (7) - with at least one type of metal-containing nanoparticles (8) according to plasma treatment (3d) of the substrate ( 1) with 5 to 50 at% - preferably with 5 to 20 at% - are provided.

8. The method according to claim 1 to 7, characterized in that a hydrocarbon-containing, adhesion-promoting protective layer (6) below the cover layer (7) in a vacuum chamber (20) from a plasma discharge to the substrate (1) is deposited at least in some areas, which at least one hydrocarbon-containing gas is supplied, and that a layer thickness is generated which is in the range of 2.0 nm to 500 nm.

9. The method according to claim 1 to 8, characterized in that a silicon oxide-containing protective layer (6) below the cover layer (7) in a vacuum chamber (20) from a plasma discharge to the substrate (1) is deposited at least in some areas, which at least a silicon-containing and at least one oxygen-containing gas is supplied, and that a layer thickness is generated which is in the range of 2.0 nm to 500 nm.

10. The method according to claim 1 to 8, characterized in that the hydrocarbon-containing, adhesion-promoting protective layer (6) at least in some areas with at least one type of metal-containing nanoparticles (11) in the range of 5 to 50 at% - preferably from 5 to 20 at% - is provided.

11. The method according to any one of claims 1 to 10, characterized in that as substrate (1) a plastic or a metal is used, preferably a ductile plastic, a ductile metal or a metallically coated ductile plastic.

12. The method according to any one of claims 1 to 11, characterized in that the protective layer (6) is deposited with a thickness in the range of 2.0 nm to 50 nm.

13. The method according to any one of claims 1 to 12, characterized in that a thermoplastic is used as the plastic of the substrate (1), preferably polypropylene.

14. The method according to any one of claims 1 to 13, characterized in that the line-like or lattice-like microstructure (2, 3) of periodically repetitive, the same structural elements (3) is generated, preferably by mechanical impressions.

15. The method according to any one of claims 1 to 14, characterized in that the microstructure (2, 3) is produced by a hot stamping process.

16. The method according to any one of claims 1 to 15, characterized in that for the substrate (1), a tape is used, preferably a film, a membrane, a textile and / or a fabric.

17. The method according to any one of claims 1 to 16, characterized in that for the substrate (1), a three-dimensional body is used, which is surface-treated inside and / or outside.

18. The method according to any one of claims 1 to 17, characterized in that the microstructured substrate (1) is cleaned prior to the deposition of the protective layer (6) in a vacuum chamber (20) with a plasma treatment, preferably by argon is supplied.

19. The method according to any one of claims 1 to 18, characterized in that with the plasma treatment (2b) with the two treatment steps at least in partial areas of the substrate surface (4), a nanostructure (6 ') is worked out, with the dimensions of 40 to 200 nm and with structure heights ranging from 20 to 120 nm.

20. The method according to any one of claims 1 to 19, characterized in that on the treated surface (9) of the workpiece (10), a water contact angle is generated, which is in the range of 90 ° to 160 °, preferably in the range of 110 ° 160 °.

21. The method according to any one of claims 1 to 20, characterized in that during the deposition of the protective layer (6) at least one metallhalti- ge nanoparticles (11) is incorporated, which increases the corrosion protection of the metal-containing workpiece (10) or influences the diffusion properties of permeating compounds.

22. Workpiece comprising a substrate (1) structured and coated on at least one side on the surface (4), characterized in that mechanically at least in partial areas a microstructure (2, 3) with indentations or elevations (2) is embossed a plurality of contiguous structural elements (3) with individual dimensions in the range of 3 to 50 microns, and in that between the adjacent structural elements (3) depressions or elevations are trench-shaped, which are arranged around the structural elements and that the microstructure (2 , 3) at least in some areas a hydrocarbon-containing or silicon-containing protective layer (6) is superimposed with a layer thickness in the range of 2.0 to 500 nm and that at least in some areas a photocatalytically active titanium oxide-containing layer is arranged as a cover layer (7) the outer surface (9), which with metal-containing nanoparticles (8) ver is seen and that the workpiece (10) on this surface (9) has a water contact angle of> 90 °.

23 workpiece comprising at least one side of the surface (4) structured and coated substrate (1), characterized in that mechanically at least in partial areas a microstructure (2, 3) with depressions or elevations (2) is embossed, consisting of a plurality is formed of contiguous structural elements (3) with individual dimensions in the range of 3 to 50 μm, and that between the adjacent structural elements (3)

Structural elements (3) depressions or elevations are trench-shaped, which are arranged around the structural elements and at least in subregions a at least one metal-containing nanoparticles (11) containing protective layer (6) is stored, which is a diffusion barrier relative to the uncoated substrate (1) and that, at least in some areas, at least one further layer is used as cover Layer (7) is arranged with the outer surface (9) and that the workpiece on this surface (9) has a water contact angle of> 90 °.